CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '9134a60e993fa042',cH: 'D.1OZKngkUta6Hv61tYsK5cKxD4jwp9eOWrtLZ3v5ao-1739783472-1.2.1.1-04JbG2XXBS.F7fflWMmEfiAzIuCPKk0Mrx6vMIwo9uK5YX2ZZbjG2RFjGZDj9sxK',cUPMDTk: "\/search?q=current-mode&__cf_chl_tk=G2ML26TbvTLm5aFygHKaMSK0sYzEM.KYe3988kAToLk-1739783472-1.0.1.1-bE2uU0m9UTalT.af6nZfYXFOrQOG2tMURVnLh3TJV3Q",cFPWv: 'b',cITimeS: '1739783472',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/search?q=current-mode&__cf_chl_f_tk=G2ML26TbvTLm5aFygHKaMSK0sYzEM.KYe3988kAToLk-1739783472-1.0.1.1-bE2uU0m9UTalT.af6nZfYXFOrQOG2tMURVnLh3TJV3Q",md: "XW8gR2E_LCb4j5mTrRt8QbjVGpf4XFkKThDTL6G9b7U-1739783472-1.2.1.1-0vec2Hs1ozycKxhIByVFcuWEBkDaDIkj.sXTaNfNn.q9rtET6PgAFJL7poZxqe01LAfjshEE892o.OlaZW4VgjbCVAikX.8GnvmTuHLp3vgCkPbIwRB.Przw89PaMxfPg77_P_xjoQBwv38y_RmIau8CYlD_URUTyCE03_YXmp8F5FbQ3hhLJ2Xadta7qsTUXJuBL_3sVWwf6UJFOm8k.UjvOyKaxoKF7IFtyyy8SSDNTB2ICnSMjWW8qx17_WqHOEVnypSfz2Fc1VOpQbFymRhde8hYl0KHbT6gGVdpNzaEl1gvZp3ju3f8Ks4Gr4bZWd._qaYmFn0UDCHmT3tmToLCYCti_yDwT5iDAxQrd3dGLVj91e9UrMPtgJCS5ty79Q_08nODUMlUDe.D843uYWUysnN7Wpi8chGibz.yb3U.4tWkxBw96O9.ydacCq0A0k5fY8Ty3irh7jgBFjS3dD0rRxFa0NU81t7v8T5cqwqgsNhvH5IJKKKR.OoNS41DbOJTDIgMoUMkFU2qLq.lZoQ8pNnQjCcIcd0nEeCAdPeaF8p138oQvfLEKplatyO2EbKUAMm2J54KBI32R.Egaf0xdmTA7h6cPs7SYqEofxxM9xfDJW2026be3dy.rzaM_d45THU.2Y_jKaLFcM0KEY9RekBNQd9wgQjU_XngERuLPhkCmWtGnnUOT72U_6w8N7lgDxrbMIQGG3Cnd3x5WbnU0.Xb8bfBfZjujDb84b5BKnEsXOA6xQ0mAyf2obcpTJLDGI9ikJ2sGBFYfpM2PNZWBfqsl41W4SxUI23Lqe0mFn5NDFenmRI4lmjOebzaZovdIvU4bB1aLeMVCTJ75Cja8J0WXnD6vE3kxDSSyzY1cDJtKy22mZCAhcBWiFA8GInalad8rTdEPEDKbNcYnW1AQTcrhfI2MHrcBW6HIjSxC6PIMDBv1qckOqgv5hheyGwrI1OK7yh3ODb2foCbNlJVQjILpiW4NLrM4q2XCNr.coxVPzWiyBxD8NzkJmRN0EU6KAS0yD5TuUWwTr2PPU6V10G0_5pcSFMnf.eZSDecoJ989DyY4o.ZktQbDKzRgTnbbLhwcBXANHJtefPsppT62pTRDGt0v.TdivBICLWiSMuf10jZh07WqU3RORJmLj3eNiant_MLDO6kDAt6SUHSCuhNXG4pyIrhQzINuBydXJ15fibas4I5Oc7s_HcOBffVxkKaqXgcxDBI5Yufn6kC9RS.UNSuJl5VC8Jhl3OpypIZ0IpnvBkA3LEmDXwy6Ib3ls3EpzzksNUVqqgUMQ3AV79I.O0wxCqJjgYcnOLwvupluuoBx9eDbE35HrohXI39yVtzalenVVEaeaCRh0TUzXnH31aOnzdqzmHUQMwoupRMCtkQ08qF8R4YRdMz54lIQzzIVXHthabCiY8opYN7AIaCJBXiqrZTFgUSJ4F3duXFyzE2sffeGCpIUkHYaeeVcr6X4hs4ka0W2sLyQK_kmM3Yekd5mjMZAwl1BdF2VWfNaLjvjuBjwZozqqd5AQDyIJdcaLg58qs.H3sQ7xmg_gOqqmqwSPy1LHwGa5UqAjvUWf0Zfpw1Q.0zCKeJrod9pjSpnD4mid0tbA3_YsGOze.218q27nTySZoOH6uQ4ENzGPtjOj0t7EkNIbNCW0zsBegYT75VK.C9espJzGcGUOkPFfB4nPpH9QnLQe42ni7HgNU6Kr1ulFhLJ2B9LRae8XVO5VMSzObkjQFPtdEGSgXlEdAIfyn2eiWIAjUfdqB9fBpQ4SkDM6kUq3rDaR5u6c00jD.8wsLNmYpmmCu5uD.oJfNkNzV3mqqShLb38BAWupm05aJ61gR63ucQFMawtHhBC9kplJMLrDCFH114qjk4Ad4M6_A7BF9T7wBisXwKaz5za4ZL3PpVJmgi",mdrd: "ecqKyCV.DkFkUvQ.Sg2th02Z4NJq37qBMKjMl4mzsA0-1739783472-1.2.1.1-wSulm6Vv8nUOGdmfj3CQcAezYQ2IUh.XQy8wT1NMkIAJXQGeg4VOP0b_a3kZua7YnUjxyyQN_E.HKzHGaDpKu_wXAgT7ZH7JQ8UBE4o2.5xL.TAaL88VCFY6FXXmlSpOHjcDyp4GIBq1WLIDYFq.FZkRh3LgTVWsV0JWNE9MyyY4n18dfimx7P7eWxSejcMrIvBZCidwSeInkEa5TTSzILa2ggcqeCaLuguC44cQEmWDBStpAodJCrO7LSr_mcKGXcTBdGp1L_JLVyxNSYy3f5JpJECQjB88akN29zn5W6imk1HOIVP6wHYNwydI1jOCJfaTB2oqkCc45xCD_Ua5Ug2So.LPegCUNPg1QDb7kUqh6uQp0E009MPIfxHK1jT41byIbeVUGAUs6Nx7kNDNk27R49pm.oq8rDXwNtJNer1A_azz5laG1eqKQ9sOI0z.cgIap6jC2y8eybOTR_vhhFtUcTYh1SjkveIdYrrgLpTqcTRkSuqLYLIQ8q8VdX7jOFa20Qd09BfZAAnJTHEkbDFCwhYbRq6HiEpreukrxGbu8ydUpsrpxwO0uH_oRAcFbUsXdOKfbU6r0moYS5kZ_mGVM13y9FNOYRxTK1vMPoey7iHVy.68q3hFPc.npv9yrg5HSkJ4Wq2Uw3FbIRTjOZgB06.KSbIKUC7m7uyREDb2vL44__k_2yqH8hEsGaA8IIsVUUM8KKRz.4MbYMIIO_oWdKXAKcyIZok9o0UK9.hkLdvYT21umLpDCVoZ9E6Savy3wVMUm09lFmf9ibYH6g2_KFDzYloMIScYPAyTwgdO6rtgCokjkJ5ZiZmQOOQ6XLqJ.1PfgwPOPUTPqKGtOfRWx1ynRNpNnpos4FYK0rzcBJKiF9ve6ElrYuob7_cSicepPlyH4NWvbycQAvbZzmRUXGGNHXDMpP1hjT6uzxY4Rdd6kvjZl18k.HiqGJRV708natcdtWxrGp_2yluwrjnfEZ.DvGuSNLzo4DHcnqIktXGUwbGhvZDmq1rDX7rDQ6Gi16Z8Yhur8nQFHPM6m_O0eCrB.Gpa9aT5Ofl20NY1QwFCJs0SQ67wWO0b_oljJFR5_FV6LgUv2DVvV7a3bgtTIlYdOsCI9A4E4a_.vPNVjv70.QXaC46YKOZ5vDgDrMdt_IXGdFAKQ7eNXAgdfSom2PJBl1IK9CK0BhB6GwR_OT8nZ7XcNTjpn6uQe1qzM3wePXgdxyh.a6xIoCzvSTXMGcUtfZdeKDbdbyQNW4aqo4Sii9f2ylaiQ2i3ZCgBkzgqC0Npw7BChxfktirraT2BeHnHJbLxYx9YRV_4KFATiZnp.ZCAgiJoXmB0htSOF7TjCFyQh0QDK1dZ0l4GVolYih.wkVqA2tKqYgudto8xKLDCi6cuO2vPu.odL8OA6L9cTucxGPKdp1atn_1ctUVhktKEEc4broCsVCWa7isT91i__GMQH8y48v930RF2RsTXMm9JM3iYvBUe4WlVcAYnFHbL57C9a6iky3KMw.DllHY4VbDXs36nVm0RTkZ7Cnj_p5jaundrw3y8qy6BFo.4d1En5CZ0Tv7oVvLsJUY87nqBy0lbpR6jlbbT7ZYxpNNdDRC4h06EDavYVlDMc2za7NMQ6IBegOhYCS1I3foSRdqQvla.gTcKLOJZs_zeEezKhKLbcdOZucE3C2RRTzWsb7rN_h9n1i3HSSj2VfXhbuuVTMDVjYhiDSDpb8pUuQ_CK9cyMRPkX_HTvHkytPeNgLUgURXwPQsHcFYsIoVtko.SMGRX8vpUgTdQdQFvwvHN6NBDN6nl0ApI5wfHK7QqnCt5Qpn6maRPp4CnphwbM3C8lRGCzlkzDVegeQhbaO6Xo.n4QauR0nsVO9jV9iSbsfhcEoM_D7BNGBirlu4h7iAqxz7qaED9LlRWbs0aew6jI8j0v2zDd.6B6S4Qj4cYui88RXljiVsSSzZ8xuVDAdJYFcBZRCwPuyN5Dpr9WHJEVtuobQQ45S7mfMDVSA"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9134a60e993fa042';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/search?q=current-mode&__cf_chl_rt_tk=G2ML26TbvTLm5aFygHKaMSK0sYzEM.KYe3988kAToLk-1739783472-1.0.1.1-bE2uU0m9UTalT.af6nZfYXFOrQOG2tMURVnLh3TJV3Q" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>